How do activate a gsm SIM Iphone 5s to use as an iPod touch?

I don't want to buy a iPod touch. I want the 5s cause of the touch I'd.

You don't need a SIM if you want to use a phone with no data connection or service.

A SIM is used to identify you as being a customer of a service plan with a carrier. It bears your phone number and allows you access to the data service.

Doesn't make much sense to buy a more expensive device to act as a less expensive one, in particular over 1 feature. Yes Touch ID is convenient but not worth spending 100s more for in my opinion.

Reports came out today that the iPod touch could be updated as early as next week Tuesday, Touch ID could be an option.

At least wait until then.